The invention relates to a vehicle bumper assembly with a bumper cross member and at least two energy absorption components arranged at a distance from each other. The energy absorption components are connected to the rear side of the bumper cross member and each have a first end and with an effective absorption direction (x direction) aligned transversely to the longitudinal extension (y axis) of the bumper. The energy absorption components there are supported on the end facing away from the bumper on a chassis part of a vehicle.
Energy absorption components, so-called crash boxes, are arranged between the bumper and the chassis of a vehicle for absorbing kinetic energy that acts on the bumper of a vehicle in case of an accident, in particular in the low speed range. These energy absorption components are typically connected to the longitudinal vehicle carriers associated with the chassis. Energy absorption components of this type are manufactured from metal or a composite material. For example, they can be box-shaped components manufactured from steel sheeting. Aluminum extrusion profiles are also used These energy absorption components are folded together in the direction of their longitudinal axis like an accordion or a bellows for purposes of absorbing energy. The reforming process absorbs the impact energy. At the same time a delay of the impact into the vehicle chassis takes place due to the buckling process as these components are folded together in the previously described manner. In these vehicle bumper assemblies the planes of the front end face surfaces of the energy absorption component are arranged either according to the introduction of force of the AZT structural test, that is, at an angle of 10° to the y-z plane about the x axis, or in the direction of the y-z axis (ATZ: Alliance Center for Technology).
In order to initiate the folding process to absorb any energy, a force peak—a so-called initial peak—must be overcome. If the force peak with which a first reforming processes introduced is overcome, the folding process of the energy absorption component continues with an already distinctly less introduction of force. In the case of an energy absorption component made from an aluminum alloy the initial peak can be 30 to 40 percent above the level of the force necessary for allowing the folding process to continue. These energy absorption components are designed in such a manner as regards its energy absorption that the danger of a permanent deformation of the chassis part does not occur until the energy absorption component has been folded together to a block. This means that, the energy absorption component has lost its ability to function as an energy absorption component. For this reason, the level of the initial peak for starting the energy absorption of such a component must be below the force at which a permanent deformation of the chassis part begins or is to be feared for the part the energy absorption component or components are connected to. Thus, the possible absorption of energy in the design of such an energy absorption component is decisively determined by the level of the initial peak, that is, by the level of the force necessary for starting the energy absorption process.
In order to counter this disadvantage, energy absorption components of the cited type have been developed into which weak points were introduced, for example, by impressing given bending lines or folding lines or by introducing perforations. The level of the initial peak can be reduced with such measures but this requires additional, cost-intensive work steps. There is therefore the desire to further improve such energy absorption components as regards the addressed problem. Furthermore, it would be desirable if the length of such an energy absorption component can be held as small as possible.
WO 97/03865 A1 describes a bumper assembly in which the energy absorption component is manufactured as an extruded aluminum alloy component. The front surface of the energy absorption component is designed as a hollow chamber profile, with an oblique front surface facing the bumper cross member. The bumper cross member comprises a receptacle into which the oblique end of the energy absorption component is inserted. The oblique surface of the energy absorption component, which surface is supported by a punctual contact opposite the back side of the energy absorption component, is arranged at an angle, leaving an angular slot. In this previously known bumper assembly, there is the danger that the regulatory assembly between the bumper cross member and the energy absorption component changes relative to one another in the case of an impact. In addition, very precise care must be taken during the manufacture of the parts and of their assembly that in order to realize the punctual support the described slot between the front surface of the energy absorption component and the back side of the bumper cross member is present.
A side frame structure for vehicles is known from DE 196 35 285 A1. The side frame structure consists of two U-shaped half-shell segments. The side frame structure functions such that an airbag ignition takes place only upon a medium severe impact. To this end the front side of the side frame structures is beveled relative to its upper segment opposite the back side of the bumper cross member, and that the end of the lower segment in this regard is spaced offset from the oblique ends. The side of this side frame structure which side faces the bumper cross member is at a distance from the back side of the bumper cross member.
The foregoing example of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.